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Ford Repair/89 f150 4.9i6


QUESTION: drove the truck to the gas station the other day as i pulled in it acted like it was running out of gas i shut it off filled the tank and it now wont start i ca hear a fuel pump come on sounds like its at your feet on driver side it only has one tank does the cut off switch work both pumps or justthe one in the tank i replaced the filter and nothing changed i dont know what to check next...thank you for your time .....brian...

ANSWER: You will need to determine if the engine is lacking fuel pressure, or ignition spark before proceeding.

---------- FOLLOW-UP ----------

QUESTION: its def lacking fuel. as long as you spray starter fluid it starts fine but doesnt stay running

Unless you can put a fuel pressure gauge on this, you will not know for sure what is being supplied to the fuel rail. You can check the electrical side in a couple ways. First use a 12 volt test light or voltmeter, locate the fuel pump relay, and check for power on the brown wire. Do this with an assistant if possible to turn the key on, as it will show power for a few seconds until the engine starts.

If you have power on that circuit, move inside near the park brake pedal, that is where the inertia fuel shutoff switch. You will find the same brown wire on one side of the connector, and pink/black wire on the other side. When the key is turned on, there should be power on both sides of this switch momentarily.

With power at this point, you should move under the truck and find the fuel pump connector, back probe the pink/black wire, turn the key and check for power (remember, this will be momentary, unless the engine starts). If you have power there, check the ground G801, behind the left headlamp. If the ground wire is tight, and you have power at the fuel pump connector, most likely the pump has failed. Have seen some that even melted the connector on top of the tank.

Good luck

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I am a retired Ford master tech specializing in electrical, climate control, emissions, driveability, chassis, brakes, and any light repairs. Cannot answer transmission, parts, or price questions, these are not areas of my expertise.


39 years of auto repair, diagnosis, and emissions testing, in service staions, independent garages, and 20 years with Ford dealers.

National Street Rod Association (NSRA)
International Automotive Technicians Network (IATN)
IAMAW (retired)

Riverside City College Automotive technology program
Ford Master Tech Certified Engine and Chassis Master (Over 500 hours)
ASE Certified in 7 categories
6 years training in Union 76 Pro-tech program

Awards and Honors
4-time Technician of the Year at Almaden Lincoln Mercury
Ford Master Tech
Union 76 Pro-tech Master tech

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